综合物探方法在西藏冈底斯成矿带西段鲁尔玛斑岩型铜(金)矿的找矿应用

鲁尔玛斑岩型铜(金)矿区位于冈底斯成矿带西段,是南拉萨微陆块中新发现的铜(金)矿,具有钾硅酸盐化、绢英岩化、青磐岩化等明显的斑岩型矿床蚀变特征,含矿斑岩为晚三叠世石英二长斑岩。通过1∶50000矿产地质专项填图、磁法扫描和水系沉积物测量发现了鲁尔玛地区铜金矿化线索,为进一步查明异常源属性和铜矿地质特征,在综合研究基础上实施大比例尺磁法、电法测量等物探工作,同时利用钻探和槽探施工进行异常查证,进而发现了铜(金)矿体。大比例尺激电、磁测和测深结果显示,发现矿化区域的北东部和深部存在低磁、低阻、高极化等有利异常,认为该异常区具有较大的找矿潜力,通过地质勘查工作可望提高铜金的资源量,扩大矿床规模。同时,对矿床发现和评价过程中找矿技术手段选择的实践表明,在高海拔地区采用高精度磁法和激电测量是快速圈定斑岩型铜矿靶区的有效勘查手段。

Application of integrated geophysical methods to Luerma porphyre Cu(Au) deposit

Luerma porphyre Cu(Au) deposit is newly discovered in the South Lasa micro-continent block in the West section of Gangdise ore belt. It is characterized by the evident porphyre-Cu-deposit related alterations, such as K-silicatization, phyllic alteration and propylitization. Quartz monzonite porphyre is the ore-host rock. Specific geological mapping for mineral resources investigation at scale 1:50000, magnetic survey coverage and river sediment survey provide ore clues of the deposit. Based on comprehensive study magnetic and electric survey at big scale were completed to make clear of attribute of source of the anomaly and geological characteristics of the deposit, and drilling and trenching conducted and Cu(Au) ore bodies encountered. IP, electric and sounding survey at large scale shows low magnetic, low resistivity and high polarization anomalies in the northeast and to depth of the mineralized area. The anomalies are potential for further exploration so as to enlarge size of the deposit and volume of the mineral resources. Practice of exploration of the deposit proves that high precision magnetic and IP survey is an effective method to locate prospecting targets for porphyre Cu deposit in high altitude areas.